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Notes: Magnetic-optical film (hereafter, MO film) is a bismuth-doped iron garnet film grown on agadolinium gallium garnet substrate by liquid phase epitaxial method. Because an MO film hasphysical characteristics such as Faraday rotation and magnetic anisotropy, the distribution of itsexternal magnetic field can be visualized. The MOI (Magneto-Optic/Eddy Current Imager) wasdeveloped to detect far-side cracks and corrosions in aluminum alloy materials on an aircraft. Thedetection probability of 2.5mm-length cracks is 90/95% when the MO film and the induced areacurrent are used. However, the quantitative evaluation algorithm for quantifying crack shapes andsizes has yet to be proposed. This paper investigates a quantitative evaluation algorithm for magneticoptical eddy current imaging by using the finite element analysis methods (FEM) and experimentalresults. The MOI including a primary induction coil was simulated by FEM software. The position,depth, shape, and the induction current frequency, lift-off were simulated and examined. A simplifiedquantitative evaluation algorithm for MOI is proposed by using the analysis results

Notes: Three types of austenitic stainless steels JK2, JJ1 and JN1 were isothermally aged at temperaturesfrom 600 to 900°C for 10 to 1000 minutes in order to study the microstructural evolution and itseffect on the fracture toughness at cryogenic temperatures. The Charpy V-Notch fracture energy at77 K showed a significant decrease with aging time in JJ1 and JN1 steels because of their highercontents of C and N. In contrast, the fracture energy corresponding to the aged JK2 steel decreasedgradually with aging time. The abundant intergranular precipitation of carbides and nitrides seemsto be the responsible for the fracture toughness deterioration in the aged JJ1 and JN1 steels. On theother hand, the intergranular precipitation of carbides was less abundant in the aged JK2 steel. Thescanning electron microscope fractographs of the CVN test specimens corresponding to the agedJJ1 and JN1 steels showed mainly an intergranular brittle fracture and its fraction increased withaging time and temperature. In general, the presence of a more abundant intergranular precipitationresulted in a more rapid decrease in toughness with aging time

Notes: 1. Pharmacological inhibition of nitric oxide (NO) synthesis is known to produce acute and chronic hypertension in many animal species, but the underlying mechanisms mediating the hypertension are not completely understood. In particular, the pathogenetic roles of sodium sensitivity and the sympathetic nervous system in this model of hypertension are controversial. The present study was designed to test the hypothesis that long-term administration of the NO synthesis inhibitor NG-nitro-L-arginine methyl ester (L-NAME) to male Sprague-Dawley rats would produce a sodium-sensitive hypertension and that the enhanced activity of the sympathetic nervous system in this type of hypertension contributes to the sodium sensitivity.2. NG-Nitro-L-arginine methyl ester was added to drinking fluid for 8 weeks at a concentration of 16 mg/dL. Rats received tap water for the first 4 weeks of the study and were then divided into two groups and placed on either a normal or high sodium intake (ingestion of either tap water or 0.9% NaCl, respectively). Awake systolic blood pressure was measured by the tail-cuff method every week. Urinary excretion rates of the stable NO metabolites and catecholamines during NO synthesis inhibition were examined.3. Long-term administration of L-NAME produced a marked and sustained elevation in arterial pressure without altering urine flow, or sodium excretion rate. NG-Nitro-L-arginine methyl ester-induced hypertension was accompanied by a decreased urinary excretion of the stable NO metabolites NO2– and NO3– and was aggravated when rats drank 0.9% NaCl in place of tap water. Urinary excretion of adrenaline and noradrenaline, but not dopamine, in L-NAME-treated rats increased significantly within the first week of the study compared with control rats. L-Arginine (2 g/dL in drinking fluid) completely reversed the elevation of arterial pressure as well as the decrease in urinary NO2– and NO3– excretion and the increased urinary excretion of catecholamines associated with L-NAME treatment by 3 weeks of concomitant administration.4. These results suggest that long-term inhibition of NO synthesis produces a sodium-sensitive hypertension and that changes in sympathetic nerve activity may, at least in part, contribute to the sodium sensitivity in this type of hypertension.

Notes: It is well known, that thermally grown oxide (TGO) forms at the interface between the thermal barrier top coating (TBC) and the bond coating during service. In previous work, SEM images showed that the TGO layer contained at least two layers with different oxides. One layer was Al〈sub〉〈/sub〉2O〈sub〉〈/sub〉3, and the other was a mixed oxide of NiO, CoO, Cr〈sub〉〈/sub〉2O〈sub〉〈/sub〉3, and their spinels. It was supposed that a reason for macro-crack formation near an interface is due to a decrease in bond strength or to the formation of stress concentration sites caused by the formation of pores in the mixed oxide. In order to improve the bond strength, a modified bond coating material was developed, which is MCrAlY with Ce and Si added. Four- point bending tests were carried out to measure the bond strength of conventional TBC and of the modified TBC with MCrAlYCeSi bond coating. As a result, the TBC with modified bond coating had a bond strength superior to the conventional one. It is likely that the reason for the superior bond strength is due to a notable difference in oxidation behavior

Notes: In general, the S-N curve in railway axles was mainly carried out under 107-108 cycles, while the service area of a railway axle is 108-109 cycles. The strain gages using electrical resistance have been used to measure stresses in railway vehicle wheelsets. However, there are some problems with strain gages using electrical resistance for railway axles. For example, the measured data is for special or limited intervals only. Strain gage installation is complicated, that is, it requires lead wiresfor measurement. The design of railway axles makes use of data that was obtained many years ago. The applied stresses in wheelsets running for a long time and in new railway vehicle wheelsets have not been studied clearly yet. It is necessary to carry out stress monitoring for more than 108 cycles to evaluate the safety of railway wheelset. Therefore, it is necessary to develop new stress monitoring techniques that can easily measure the working stress of the wheelset. In the present paper, the stress measurement technique of copper electroplating is considered because of its high potential for this purpose

Notes: The effect of grain boundary character distribution (GBCD) on intergranular stress corrosion cracking (IGSCC) in austenitic stainless steels in high temperature water was verified experimentally. GBCD control using the strain annealing method increased the fraction of low- S coincidence site lattice (CSL) boundaries and the segmentalized network of random grain boundaries in austenitic stainless steels. The fractions of low- S CSL boundaries of GBCDcontrolled steels were 75–85%, while those of uncontrolled steels were 60–70%. Creviced bent beam tests were conducted at 561 K in pure water containing 8 ppm dissolved oxygen for stress corrosion cracking (SCC) evaluation. The tests revealed that GBCD control suppressed IGSCC initiation or propagation and that cracks were predominantly propagated along random grain boundaries. It is considered that induced lower- S CSL boundaries result in high resistance toIGSCC

Notes: A possible approach to describe the role of the environment in the phenomena behind crack initiation and crack propagation in stress corrosion cracking (SCC) is to assume that the transport of species through the oxide film on the material surface is one of the rate-controlling factors. The transport rates of ionic and electronic defects through the oxide film are, in addition to the environment,also affected by the stress and strain applied to the bulk material.In this paper, the surface oxide film formed on AISI 316L steel in slow strain rate tests (SSRT) in simulated BWR condition has been analyzed by using Electron Spectroscopy for Chemical Analysis (ESCA). The obtained film composition and structure have been combined with in-situ contact electric resistance (CER) measurements in order to evaluate the changes in oxide film electric properties during straining in the above environment. The results show that oxide film resistance of the strained part exhibits a maximum at around 2% of strain, which seems to correlate with a maximum in the Cr(III) concentration in the inner layer of the oxide. The implications of these results to SCC are discussed based on Mixed-Conduction Model (MCM)

Notes: Previously, we proposed stress corrosion cracking model on the basis of interaction of dislocation and hydrogen around a crack tip to predict discontinuous cleavage-like fracture during stress corrosion cracking (SCC) for ductile fcc alloys. Furthermore, we conducted numerical analyses using this proposed model. In the analysis, hydrogen was treated as a static cluster. However, actually, both of hydrogen and dislocations move with interaction each other. Therefore, in this paper, a physical model of dislocation and hydrogen dynamics with interaction was proposed. And the behavior of interaction between dynamic dislocations and hydrogen was investigated. On the basis of this analysis, the discontinuous cleavage-like fracture during SCC for ductile fcc alloys was clarified